Star Trek copied the Navy (US&UK style) of addressing all senior officers as Sir, regardless of gender.
"Man" was originally a gender-neutral Old English word for human beings (the gendered prefix for males being "wer", as appears in e.g. werewolf.) So why not just expand on that: demand that "man", "sir", "he", "him", "Mr"—and common nouns like "mailman", "fireman", "steward", "host", "master"—be used when referring to both men and women, and thus retroactively de-gender all previously written implicit-male-subject texts for future generations? Instead, we got "he/she", "they", "mail carrier" and "fireperson", which seems like a terrible thing to do to a previously-concise language.
Shakespeare still would use "he" or "she" as appropriate when trying to make it explicit that there was exactly one person being referred to.
But now, we are told to use "they" or "he/she" even in that situation, because singular-generic "he" is offensive to some people, and because human-referential "it" is offensive to rather more people.
Taking offence to a communication protocol, is like saying TCP/IP is offensive because there aren't enough of the number 7 used in the TCP/IP protocol, and it's discriminating against the equality of all numbers.
No. It's a protocol optimized for communication, not some sort of emotional playground.
To try to alter the communication protocol based on personal emotions degrades its usefulness and diminishes the ability to communicate effectively.
So now the TCP/IP packet header needs to be extended 25%, and the driver needs to ensure equal distribution of all numbers during communication, further increasing overhead by another 75%.
This is where we are headed with our language, when we allow PC politics to dictate how words should be used.
Unlike machines, humans do not always just want to exchange factual information about the world, and often use communication for additional purposes - jockeying for status, claiming membership in groups, and yes, playing games. This can even be quite enjoyable for the humans in question, for example, mutual flirtation.
In this example, one of the bits of information that can conveyed by being a bit more thoughtful about the use of pronouns is where the human in question might fall on a scale between "I am aware that there is pervasive and systematic discrimination against one class of human, and do not wish to take even small part in it." and "I believe all relevant systematic discrimination is in the past."